agents: add AGENTS.md + .agents/ scaffolding (wiki/plans/skills stubs)

Adds the root AGENTS.md entry point and minimal .agents/ skeleton
(SOUL, wiki/master-plan+ARCHITECTURE, plans/, skills/) per the
per-repo-agents-convention. Existing handoffs/ untouched.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.agents/SOUL.md

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+# SOUL — tinqs/builds
+
+Inherits the shared Tinqs identity, values, and confidentiality rules from the hub:
+`tinqs-ltd/docs/.agents/SOUL.md`. Read that first.
+
+Nothing repo-specific to add — this is a build artifact store, not a product with its own voice.

.agents/wiki/ARCHITECTURE.md

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+# ARCHITECTURE — tinqs/builds
+
+Build artifact repo, not a codebase. There's no runtime architecture to document — the "system"
+is a flat, LFS-backed artifact store plus a manifest.
+
+## Layout
+
+- `engine/<platform>/` — engine editor binaries + their matched `GodotSharp/` C# bindings
+- `manifest.json` — exact versions/commits for each shipped artifact
+- `.gitattributes` — Git LFS rules for binaries and GodotSharp
+
+## Law
+
+Binary and `GodotSharp/` for a given engine build are a **matched pair** — always install/replace
+together. See root `README.md` for the full rule and current per-platform status table.
+
+See `architecture/` for any future per-system breakdowns (none yet — repo is single-purpose).

.agents/wiki/architecture/README.md

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+# Architecture docs
+
+Per-system architecture notes go here as this repo grows beyond a flat artifact store.
+Currently empty — see `../ARCHITECTURE.md` for the current-state summary.

.agents/wiki/master-plan.md

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+# Master plan — tinqs/builds
+
+## Current state
+
+Build artifact repo: stores engine editor binaries + matched `GodotSharp/` C# bindings for the
+Tinqs/Ariki stack, plus `manifest.json` tracking exact shipped versions. Source lives in
+`tinqs/engine`, `tinqs/ariki-game`, `tinqs/ariki-sim` — this repo only holds built output.
+
+- macOS arm64: engine 4.7, native Terrain3D module, GodotSharp shipped.
+- Windows x64: engine 4.6.5 (pre-4.7), GDExtension Terrain3D, 4.7 upgrade pending Forge —
+  see `.agents/handoffs/forge-windows-4.7.md`.
+
+## In flight
+
+- Windows 4.7 engine build + matching GodotSharp (blocked on Forge machine — see handoff).
+- Longer-term: CI (Gitea Actions) building on push and publishing here / to S3 — tracked in
+  `docs/ai/plans/build-pipeline-architecture-2026-06-07.md` (hub repo, not here).
+
+## Recently shipped
+
+- macOS arm64 rebuilt on 4.7 with native Terrain3D + agent_skinned modules, Tinqs branding restored,
+  GodotSharp regenerated to match.